Soil Quality Index (SQI) for Eurasia

The Soil Quality Index (SQI) is serves as a measure for the agricultural potential based on various soil parameters. The SQI is based on the Müncheberg Soil Quality Rating (SQR; Müller et al. 2007). Here, we rescale the SQR using min-max normalization to describe the agricultural potential of soils on a scale of 0–100. Then, we extrapolate the data across continental Europe by projected the SQR for Germany on a map of soil types in Europe from the European Soil Database v2.0 (ESDB; Panagos et al. 2022). Using the mean function from the zonal statistics plugin in QGIS (Version 3.34.3-Prizren), we calculate the mean SQI within each soil type polygon. Using the WRB Classification, we average the SQI across all polygons of the same soil type and interpolated the SQI on all polygons of the ESDB map (Europe and Eurasia). Since not all soil types contained in the ESDB are present in Germany, no SQI could be derived for some soil types and some manual corrections were required to fill remaining areas. This included implementing SQI values for parent categories or an FAO-based classification, where values for specific soil types were not available; manually setting the SQI to 0 for areas (e.g., marshes, glaciers, and rock outcrops) as well as soil types (e.g., Cryosol and Solonchak) unsuitable for agriculture. Lastly, we manually defined the SQI for some rare soil types based on the SQI of comparable soil types. The total area of these manually defined SQI values comprises only 2% of the total area. The SQI is provided as a GeoTIFF with a spatial resolution of 0.01° × 0.01° (~ 1 km × 1 km). An interactive upscaled version of the dataset can be explored at https://oakern.shinyapps.io/soilqualityindex/